The present invention relates in general to an autoclavable storage container for a medical or dental instrument cassette. More specifically, the present invention relates to an autoclavable storage container which is constructed with a pair of filter panel assemblies located in a removable lid. The filter panel assemblies of the present invention are designed for a replaceable paper filter which permits the two-way flow of autoclave sterilant, while blocking the entry of bacteria and contaminants.
The sterilizing of an instrument cassette which includes medical and/or dental instruments and equipment is typically performed in one of two ways. In one approach, the loaded cassette is completely wrapped in a specific type of autoclave paper which allows the sterilant to flow through the paper and sterilize the instruments and the cassette generally. When the autoclaving procedure is completed, the wrapped cassette is stored until the instruments are required for a particular medical (or dental) procedure. The autoclave paper wrapping is then removed and discarded and the instruments in the cassette are readied for use.
In the other approach, the loaded cassette is placed within a larger storage container which is constructed and arranged with at least one filter panel assembly. The storage container includes a tray portion and an enclosing lid with a compression lid gasket which is used between the tray portion and the lid. The filter panel assembly which is typically located in the lid, or, alternatively, in one of the sidewalls of the tray portion, includes a replaceable paper filter or filter cartridge. Latches, some of which may be spring-biased, are typically used to clamp the lid and tray portion together.
While the wrapping approach is relatively simple to perform and relatively low cost from the perspective of front end fixed costs, the shelf life of the sterilized instrument cassette is relatively short, estimated to be a few weeks, maximum. Further, the wrapping paper represents a continuing or repeating cost and must be discarded after being unwrapped and removed from the cassette. Unwrapping and removal of the paper usually takes place in the operating room, and thus this discarding requirement could be viewed as a disadvantage or drawback of this approach.
With the approach using an enclosing storage container, there is a front end investment for the storage container, but the continuing costs of the replaceable paper filters is minimal. While cost is one consideration, the most significant advantage of this particular approach is the extended shelf life for the sterilized cassette, estimated to be several months.
Some of the concerns with existing storage container designs is that the filter panel assemblies are often bulky, complex, costly, and frequently extend inwardly from the lid into the hollow interior of the tray portion for a distance which is regarded as unacceptable. When the filter (panel) assembly extends some measureable distance into the hollow interior of the tray portion, it reduces the available storage volume inside the tray portion and could result in limiting the storage container to smaller cassettes. Another option for dealing with the loss or reduction in available interior space is to increase the depth of the tray portion which adds to the cost and increases the required storage space for the storage container due to the increased size. To the extent that storage space in the operating room for storage containers of the type disclosed herein is limited, then an increase in the size reduces the number of storage containers which can be stored in the operating room.
Other concerns with designs of the type disclosed herein include the integrity of any sealed interface around the filter paper to guarantee that the only path into the interior volume of the storage container is through the filter paper, not around the filter paper. Accordingly, it would be an improvement to existing designs to make the filter panel assembly with a lower profile in order to make the overall storage container more compact. In creating a filter panel assembly with such low profile, it would be an added improvement to provide a design which is easy to use and which establishes a secure seal around the replaceable paper filter. The present invention provides these various improvements. Another improvement provided by the present invention is the ease and convenience of replacing the paper filter.
Another feature of storage containers of the type disclosed herein is the use of spring-biased side or end latches which are used to draw the lid down tightly against the upper edge of the tray portion. The upper edge of the tray portion may include a sealing gasket or alternatively and preferably a sealing gasket is positioned within the lid. This gasket needs to be compressed for the desired seal between the tray portion and lid to be achieved. The present invention provides an improved sealing gasket (O-ring) design which expands in sealing area as it is compressed between the lid and the upper edge of the tray portion. It is also important to have latches which are easy to use and which visually indicate both the opened (unlatched) and the closed (latched) status of the latch. Such a visual indication aids the medical personnel in proper handling of the storage container and minimizes mishandling risks. The present invention also provides an improved latch design for use with storage containers of the type described herein.